Use of plasma metanephrine to aid adrenal venous sampling in combined aldosterone and cortisol over-secretion

68Ga-pentixafor PET/CT in the localization diagnosis of primary aldosteronism concurrent subclinical cushing's syndrsome: two case reports

PURPOSE

Adrenal venous sampling (AVS) is recommended for subtyping primary aldosteronism (PA). However, in cases of PA, concurrent subclinical Cushing's syndrome (SCS) has the potential to confound AVS results. Pentixafor, a CXC chemokine receptor type 4-specific ligand, has been reported as a promising marker to evaluate functional nature of adrenal adenomas. This study aims to investigate the clinical value of Gallium-68 Pentixafor Positron Emission Tomography-Computed Tomography (68Ga-Pentixafor PET/CT) in the localization diagnosis of patients with PA plus SCS.

METHODS

Two patients with a confirmed diagnosis of PA plus SCS underwent AVS and 68Ga-Pentixafor PET/CT.

RESULTS

AVS results revealed no lateralization for both patients while 68Ga-Pentixafor PET/CT showed a unilateral adrenal nodule with increased uptake of 68Ga-Pentixafor. Unilateral adrenalectomy was performed based on the results of 68Ga-Pentixafor PET/CT. Subsequently, complete biochemical remission of autonomous aldosterone and cortisol secretion were achieved in both cases.

CONCLUSIONS

68Ga-Pentixafor PET/CT shows promising potential for the localization of aldosterone and cortisol co-secreting adrenal adenoma in patients with PA plus SCS.

The value of plasma metanephrine measurements during adrenal vein sampling

Objective

The assessment of primary aldosteronism incorporates adrenal vein sampling (AVS) to lateralize aldosterone excess. Current adrenal vein sampling protocols rely on concurrent cortisol measurements to assess successful cannulation and lateralization and may be inaccurate in the setting of autonomous cortisol secretion. We aimed to compare the measurement of plasma cortisol and metanephrine concentrations to assess cannulation and lateralization during AVS.

Design

This is a diagnostic accuracy study in a tertiary referral endocrinology department.

Methods

Forty-one consecutive patients with confirmed primary aldosteronism undergoing AVS (49 procedures) were included. None had cortisol autonomy. The use of plasma metanephrine-based ratios were compared with standard cortisol-based ratios to assess cannulation and lateralization during ACTH-stimulated AVS.

Results

There was strong agreement between a cortisol selectivity index (SI) ≥5.0 and an adrenal vein (AV) to peripheral vein (PV) plasma metanephrine ratio (AVmet-PVmet) of ≥12.0 to indicate successful cannulation of the AV (n = 117, sensitivity 98%, specificity 89%, positive predictive value (PPV) 95%, negative predictive value (NPV) 94%). There was strong agreement between the standard cortisol-based SI and an AV plasma metanephrine-to-normetanephrine ratio (AVmet-AVnormet) of ≥2.0 to indicate successful cannulation (n = 117, sensitivity 93%, specificity 86%, PPV 94%, NPV 84%). There was strong agreement between the cortisol- or metanephrine-derived lateralization index (LI) > 4.0 for determining lateralization (n = 26, sensitivity 100%, specificity 94.1%, PPV 91.6%, NPV 100%).

Conclusions

Ratios incorporating plasma metanephrines provide comparable outcomes to standard cortisol-based measurements for interpretation of AVS. Further studies are required to assess the use of metanephrine-derived ratios in the context of confirmed cortisol autonomy.

Significance statement

Primary aldosteronism is a common cause of secondary hypertension, and adrenal vein sampling remains the gold standard test to assess lateralization. Cortisol-derived ratios to assess cannulation and lateralization may be affected by concurrent cortisol dysfunction, which is not uncommon in the context of primary aldosteronism. Our study showed comparable outcomes when using accepted cortisol-derived or metanephrine-derived ratios to determine cannulation and lateralization during adrenal vein sampling. Further research is required to validate these findings and to assess the use of metanephrine-derived ratios in the context of confirmed concurrent cortisol dysfunction.

Comparison of Cortisol, Androstenedione and Metanephrines to Assess Selectivity and Lateralization of Adrenal Vein Sampling in Primary Aldosteronism

Success of adrenal vein sampling (AVS) is verified by the selectivity index (SI), i.e., by a step-up of cortisol levels between the adrenal vein and the infrarenal inferior vena cava samples, beyond a given cut-off. We tested the hypothesis that androstenedione, metanephrine, and normetanephrine, which have higher gradients than cortisol, could increase the rate of AVS studies judged to be bilaterally successful and usable for the clinical decision making. We prospectively compared within-patient, head-to-head, the selectivity index of androstenedione (SI_A), metanephrine (SI_M), and normetanephrine (SI_NM), and cortisol (SI_C) in consecutive hypertensive patients with primary aldosteronism submitted to AVS. Main outcome measures were rate of bilateral success, SI values, and identification of unilateral PA. We recruited 136 patients (55 + 10 years, 35% women). Compared to the SI_C, the SI_A values were 3.5-fold higher bilaterally, and the SI_M values were 7-fold and 4.4-fold higher on the right and the left side, respectively. With the SI_A and the SI_M the rate of bilaterally successful AVS increased by 14% and 15%, respectively without impairing the identification of unilateral PA. We concluded that androstenedione and metanephrine outperformed cortisol for ascertaining AVS success, thus increasing the AVS studies useable for the clinical decision making.

Adrenal vein sampling: technique and protocol, a systematic review

Primary aldosteronism is the leading cause of secondary hypertension worldwide. Its deleterious effects outstrip those due to blood pressure elevation alone. An essential part of the work-up of a patient with primary aldosteronism is determining if aldosterone production is unilateral or bilateral. With the former, surgery offers a potential cure and better overall outcomes. Adrenal vein sampling is considered the most reliable method to determine whether production is unilateral or bilateral. Sampling may be non-diagnostic when the vein cannot be properly cannulated. But with proper knowledge and experience as well as the utilization of certain techniques, procedure success can be high. Multiple protocols exist; their rationale and drawbacks are reviewed here. This article will give the reader an overview of techniques for improving procedural success as well as background, rationale and evidence to guide one in choosing the appropriate procedural and interpretation protocol.

Comparison of Bolus and Continuous Infusion of Adrenocorticotropic Hormone During Adrenal Vein Sampling

BACKGROUND

Adrenocorticotropic hormone (ACTH) is widely used in adrenal vein sampling (AVS) and can be administered as a bolus injection or continuous infusion. The optimal administration method has not been determined. We aimed to compare the effects of ACTH bolus with infusion on cannulation success, lateralization assessment and adverse events (AEs).

METHODS

Retrospectively collected data from patients with primary aldosteronism who underwent AVS with ACTH at a tertiary hospital in China. Rate of successful cannulation, lateralization index (LI), complete biochemical remission and AEs related to AVS were analyzed.

RESULTS

The study included 80 patients receiving ACTH bolus and 94 receiving infusions. The rate of successful cannulation was comparable between bolus and infusion groups (75/80, 93.4% vs 88/94, 93.6%). In those with successful cannulation, the bolus group had a higher selectivity index than the infusion group, while LI [6.4(1.8-17.5) vs. 7.6(2.0-27.8), P=0.48] and rate of complete biochemical remission (43/44, 97.7% vs 53/53, 100%, P=0.45) did not significantly differ between the two groups. One in the bolus and one patient in the infusion group had adrenal vein rupture but they recovered with conservative treatment. The bolus group reported more transient AEs such as palpitation (52.9% vs 2.2%) and abdominal discomfort (40.0% vs 2.2%) than the infusion group.

CONCLUSIONS

Due to their similar effects on cannulation success and lateralization, but a lower rate of transient AEs in the infusion group, the continuous infusion method should be recommended for ACTH stimulation in AVS.

Bilateral Aldosterone Suppression in Patients With Right Unilateral Primary Aldosteronism and Review of the Literature

Introduction

Adrenal vein sampling (AVS) identifies unilateral primary aldosteronism but may occasionally show paradoxically low aldosterone–cortisol ratios bilaterally. Postulated reasons include venous anomalies, fluctuating aldosterone secretion, or superselective cannulation. We report our findings in patients who underwent repeat AVS and reviewed the current literature.

Methods

We performed a retrospective observational study of patients undergoing AVS in an experienced high-volume tertiary center over a 5-year period.

Results

From 2015 to 2019, 61 patients underwent sequential cosyntropin-stimulated AVS and all had bilateral successful cannulation (100%). Four of 61 (6.6%) patients had bilaterally low aldosterone–cortisol ratios. Three patients underwent repeat AVS, with all 3 cases demonstrating right-sided lateralization and cure of disease postadrenalectomy. Right-sided disease was also more common in other reports. This may be due to inadvertent superselective cannulation of the short right adrenal vein, resulting in sampling of the adjacent normal gland. Cortisol results cannot detect this problem. In 1 patient, computed tomography venography excluded any accessory right adrenal veins. In another patient, repeat bilateral simultaneous unstimulated AVS was done, and measurements of metanephrines aided in accurately identifying right-sided lateralization.

Conclusion

In addition to technical difficulties in cannulating the right adrenal vein, we also have to avoid performing superselective cannulation inadvertently. In cases of inconclusive AVS, repeat sampling may identify patients with potentially curable unilateral primary aldosteronism. The role of corticotropin stimulation and metanephrines measurements during repeat AVS requires further study.

Primary aldosteronism concurrent with subclinical Cushing's syndrome: a case report and review of the literature

Background

The prevalence of primary aldosteronism concurrent with subclinical Cushing’s syndrome was higher than previously thought. Through analyzing a rare clinical case, we summarized the diagnosis and management of primary aldosteronism with subclinical Cushing’s syndrome.

Case presentation

A 54-year-old Chinese man of Han nationality was diagnosed as having primary aldosteronism with subclinical Cushing’s syndrome. An abdominal computed tomography scan revealed a mass in his left adrenal gland and a mass in his right adrenal gland. After finishing sequential adrenal venous sampling without adrenocorticotropic hormone, the result reminded us that the left and right nodules were responsible for hypercortisolism and aldosterone hypersecretion, respectively. Right and left adrenalectomy were performed successively. The pathological diagnosis was adrenocortical adenoma for both. Histological findings revealed that the right one had positive immunostaining for CYP11B2 and the left one had positive immunostaining for CYP11B1. The immunohistochemistry result helped us to confirm the diagnosis. Somatic KCNJ5 mutation (Leu168Arg) was found in the right tumor; there was no KCNJ5 mutation in the left adrenal tumor.

Conclusions

We suggest that patients with primary aldosteronism should have a low-dose overnight dexamethasone suppression test to screen for hypercortisolism. It can help avoid misdiagnoses and contribute to proper understanding of the adrenal vein sampling result. Making sure of the nidus of aldosterone and cortisol secretion is crucial for the therapy of patients with primary aldosteronism and subclinical Cushing’s syndrome.

[Primary hyperaldosteronism: difficulties in diagnosis]

Primary hyperaldosteronism (PA) - is the clinical syndrome, results from autonomous of the major regulators of secretion, aldosterone overproduction by a tumorous or hyperplastic tissue in adrenal cortex. Being the most frequent cause of secondary hypertension, PA may be represented by disorders with unilateral or bilateral aldosterone overproduction and differential diagnosis between them is crucial for choosing a right therapeutic approache: lifelong medical therapy with mineralocorticoid receptor antagonists or unilateral adrenalectomy. Adrenal venous sampling (AVS) is currently the «gold standard» test for identifying laterality of excess hormone production, unlike imaging tests, sensitivity and specificity of which is not enough, due to inability to evaluate functional activity with confidence, and also to limitations in detecting tiny abnormalities of adrenals, such as microadenoma or hyperplasia. Excluding certain cases, AVS is recommended to patients with confirmed PA, planning surgical treatment, to determine the lateralization of aldosterone hypersecretion. Described clinical case of patient with confirmed lateralization from adrenal without any detected lesions on CT-imaging and nonfunctioning tumour on contralateral side, highlights the importance of using AVS for decision to refer patients for surgery.

The relevance of cortisol co-secretion from aldosterone-producing adenomas

AIMS AND OBJECTIVES

Adrenal adenomas are usually non-functioning, but can secrete aldosterone or cortisol. It has recently been suggested that many more adenomas than previously thought secrete more than one hormone. This has important implications for their clinical management. Our aim was to determine the frequency of cortisol co-secretion in primary hyperaldosteronism at our institution and investigate the difference in metabolic profiles and clinical outcomes between co-secreting and non-co-secreting patients.

DESIGN AND PATIENTS

A retrospective study of 25 patients with primary hyperaldosteronism who also underwent formal dexamethasone suppression tests to determine cortisol co-secretion.

MEASUREMENTS

Post-dexamethasone suppression test cortisol, serum ALT, total cholesterol, HDL-cholesterol, LDL-cholesterol, HbA1C (were recorded) and mean arterial pressure are reported in this cohort of patients with primary hyperaldosteronism.

RESULTS

Four out of 25 patients with primary hyperaldosteronism failed dexamethasone suppression tests. This suggests a frequency of co-secretion ranging between 4 and 16%. No significant difference was found in serum ALT, total cholesterol, serum HDL-cholesterol, LDL-cholesterol and mean arterial blood pressure at presentation between co-secretors and non-co-secretors.

CONCLUSION

A frequency range of 4-16% suggests that a significant proportion of patients with primary hyperaldosteronism co-secrete cortisol. Co-secretors did not have a worse metabolic profile than non-secretors. The impact of co-secretion on metabolic profile and surgical management remains unclear and warrants further study.

Subtype Diagnosis of Primary Aldosteronism: Is Adrenal Vein Sampling Always Necessary?

Aldosterone producing adenoma and bilateral adrenal hyperplasia are the two most common subtypes of primary aldosteronism (PA) that require targeted and distinct therapeutic approaches: unilateral adrenalectomy or lifelong medical therapy with mineralocorticoid receptor antagonists. According to the 2016 Endocrine Society Guideline, adrenal venous sampling (AVS) is the gold standard test to distinguish between unilateral and bilateral aldosterone overproduction and therefore, to safely refer patients with PA to surgery. Despite significant advances in the optimization of the AVS procedure and the interpretation of hormonal data, a standardized protocol across centers is still lacking. Alternative methods are sought to either localize an aldosterone producing adenoma or to predict the presence of unilateral disease and thereby substantially reduce the number of patients with PA who proceed to AVS. In this review, we summarize the recent advances in subtyping PA for the diagnosis of unilateral and bilateral disease. We focus on the developments in the AVS procedure, the interpretation criteria, and comparisons of the performance of AVS with the alternative methods that are currently available.

New Advances in the Diagnostic Workup of Primary Aldosteronism

Primary aldosteronism is an important and common cause of hypertension that carries a high burden of morbidity. Outcomes, however, are excellent if diagnosed and treated appropriately. The diagnostic workup for primary aldosteronism is complex and comprises three steps: (1) screening, (2) confirmatory testing, and (3) subtype differentiation. In this review, we discuss recent advances in the diagnostic workup for primary aldosteronism. The development of accurate mass spectroscopy-based assays for measuring aldosterone will lead to improved confidence in all diagnostic aspects involving measurement of aldosterone, and accurate measurement of angiotensin II may soon advance us beyond the measurement of renin. We now have a greater understanding of hormonal influences on the aldosterone/renin ratio, which are particularly important when screening premenopausal women or those taking estrogen-containing preparations. Confirmatory testing is important, but there are limitations to the commonly used methods that have recently become more apparent, with new approaches offering a way forward. Adrenal venous sampling (AVS) is a challenging procedure but is important for deciding on treatment options. Success rates may be improved by the use of Synacthen stimulation and of rapid intraprocedural measurement of cortisol. Better understanding of AVS interpretation criteria allows improved prognostication and aids treatment decisions. The use of labeled metomidate positron emission tomography computed tomography scanning may also offer an alternative to AVS in some units. Although the diagnostic approach to patients with primary aldosteronism remains a complex multistep process in which attention to detail is important, recent advances will improve patient care and outcomes.